1. Field of the Invention
The present invention relates to a cabinet for acoustic equipment or the like such as a television receiver and a cassette-integrated-type radio (radio-cassette player).
2. Description of the Related Art
FIG. 11 shows a conventional cabinet for a television receiver. This cabinet is divided into a box-shaped front cabinet 1 and a box-shaped rear cabinet 2, and is formed by fitting a protruding portion 21 provided on an upper side and left and right sides of a front end of the rear cabinet 2 to the inner side of an edge portion of an opening (not shown in the drawing) at a rear end of the front cabinet 1. For this reason, the protruding portion 21 and the edge portion of the opening overlap with each other at the fitted portion. However, since synthetic resin moldings are used for both the front cabinet 1 and the rear cabinet 2, and the cabinet also functions as an acoustic box, if the protruding portion 21 is merely fitted as it is to the edge portion of the opening, the fitted portion vibrates depending on the volume of a speaker (not shown) incorporated in the cabinet, and the so-called fluttering sound occurs in consequence of the collision (contact) between the protruding portion and the edge portion of the opening, thereby possibly lowering the sound quality.
Accordingly, as shown in FIG. 11, a cushioning material 22 such as a nonwoven fabric is conventionally attached to appropriate portions or the entire portion of the protruding portion on the obverse surface side of the protruding portion 21. When the protruding portion 21 is fitted to the edge portion of the opening, the cushioning material 22 is placed between the protruding portion 21 and the edge portion 12 of the opening at the fitted portion, as shown in FIG. 12. Providing this arrangement, even if the fitted portion vibrates, since the protruding portion 21 and the edge portion 12 of the opening are prevented from coming into direct contact with each other by the cushioning material 22, situation in which the chattering sound occurs in consequence of the collision between the two members is suppressed, and jouncing the fitted portion is also suppressed.
Meanwhile, JP-A-10-59359 discloses that when a case for a vehicle-mounted electronic apparatus is formed by being divided into a lower casing body an upper casing body, a structure prevents from jouncing fitted portion of the two casing bodies. According to this publication, in a state in which one edges of two rectangular holes provided at side panels on the upper casing body side ride over semi-conical projections formed in a juxtaposed manner at two positions on side panels of the lower casing body, the other edges of these rectangular holes are separately retained. In addition, JP-A-55-179093U discloses a cabinet which is formed by fitting a projection provided on a tongue piece at a cover side to a recessed portion formed on side plates of a cabinet body. Further, JP-A-62-172180U discloses a housing for acoustic equipment or the like which is formed by fitting a projection provided on a casing side to a recessed portion provided on a cover side.
However, with the conventional cabinet described with reference to FIGS. 11 and 12, since the cushioning material 22 such as the nonwoven fabric is extra required to prevent the chattering sound at the fitted portion between the protruding portion 21 of the rear cabinet 2 and the edge portion 12 of the opening in the front cabinet 1, the cost increases correspondingly.
In addition, with the structure disclosed in JP-A-10-59359 mentioned above, since subject matter thereof is a casing for vehicle-mounted electronic equipment to which intense vibrations, such as vibrations of vehicle during running or engine vibrations, are transmitted, this publication is merely intended to suppress the jounce in the fitted portion between the lower casing body and the upper casing body as much as possible and to prevent loosening and the like from occurring in the fitted portion even if the vibrations are repeatedly transmitted. As such, no countermeasure is adopted for suppressing the occurrence of fluttering sound required for the cabinet for acoustic equipment or the like. As for the structures disclosed in JP-A-55-179093U and JP-A-62-172180U as well, these publications are merely intended to firmly join the fitted portion of the cabinet or the like, and no countermeasure is adopted for suppressing the occurrence of the aforementioned fluttering sound.
Under the above-described circumstances, the applicant integrally formed projections 23, as shown in FIG. 13 for explanation, having rectangular-shape in a front view (hereafter referred to as the xe2x80x9crectangular projectionsxe2x80x9d), the projections 23 arranged at desired intervals at a plurality of positions on the obverse surface of the protruding portion 21 of the rear cabinet 2 side, instead of using the cushioning material 22 such as the nonwoven fabric mentioned above with reference to FIGS. 11 and 12. The applicant attempted to form a cabinet by fitting the protruding portion 21 to the inner side of the edge portion of the opening on the rear cabinet side.
FIG. 14 is an enlarged cross-sectional view, taken from the front side, of the fitted portion between the protruding portion 21 and the edge portion 12 of the opening. As shown in the drawing, in this fitted portion, the rectangular projection 23 provided on the protruding portion 21 is placed between the protruding portion 21 and the edge portion 12 of the opening, and whereby a gap 3 is formed between an obverse surface 21a of the protruding portion 21 and a rear surface 12a of the edge portion 12 of the opening. It was found that when the fitted portion has this structure, even if the fitted portion vibrates due to sound from a speaker, since the contact between the protruding portion 21 and the edge portion 12 of the opening is prevented by virtue of the gap 3, the occurrence of the fluttering sound in consequence of the collision between the protruding portion 21 and the edge portion 12 of the opening can be suppressed. It was also found that when mutual interval between adjacent ones of the rectangular projections 23 is set to be quite a bit wide, warping deformation such as inward drooping of the edge portion 12 of the opening is difficult to occur, and that an action of suppressing the fluttering sound by virtue of the gap 3 can be demonstrated. However, since a flat top surface 23a of the rectangular projection 23 is in surface contact and is superposed with the reverse surface 12a of the edge portion 12 of the opening, it was found that relatively large fluttering sound can occur in consequence of the collision between the rectangular projection 23 and the edge portion 12 of the opening.
The invention has been devised in view of the above-described circumstances.
An object of the invention is to provide a cabinet for acoustic equipment or the like which enables to substantially suppress the occurrence of the fluttering sound at the aforementioned fitted portion despite the fact that the cushioning material such as the nonwoven fabric is not required.
Another object of the invention is to provide a cabinet for acoustic equipment or the like in which the jounce is difficult to occur at the aforementioned fitted portion.
Still another object of the invention is to provide a cabinet for acoustic equipment or the like which enables to facilitate an operation of fitting the aforementioned protruding portion to the edge portion of the opening.
A cabinet for acoustic equipment or the like according to the invention is formed by fitting a protruding portion provided on one of a front cabinet and a rear cabinet to an inner side of an edge portion of an opening on the other of the front cabinet and the rear cabinet.
To facilitate an understanding of explanation, a description will be given of a cabinet in which one cabinet is the rear cabinet, and the protruding portion is provided on the rear cabinet, while the other cabinet is the front cabinet. The cabinet is formed by fitting the protruding portion to the inner side of an edge portion of an opening of the front cabinet.
In the cabinet in accordance with the invention, convex portions provided at a plurality of positions on one of the obverse surface of the protruding portion and the reverse surface of the edge portion of the opening are placed between the protruding portion and the edge portion of the opening to form a gap between the obverse surface of the protruding portion and the reverse surface of the edge portion of the opening. For this reason, as can be appreciated from the description with reference to FIG. 14, even if the fitted portion between the protruding portion and the edge portion of the opening vibrates due to sound from a speaker, the gap prevents the protruding portion from contacting the edge portion of the opening with each other, thereby suppressing occurrence of the fluttering sound in consequence of the collision between the protruding portion and the edge portion of the opening.
In the invention, in addition to the above-described arrangement, a top portion of each of the convex portions is formed in a tapered or arcuate shape. If the top portion of each of the convex portions is thus formed in the tapered or arcuate shape, since the superposed area, between each of the top portions of the convex portions and the protruding portion or the edge portion of the opening where the top portions are in contact, becomes extremely narrower than the case described with reference to FIG. 14, the fluttering sound does not occur at the superposed portions, or even if the fluttering sound occurs, the fluttering sound is suppressed substantially to such an extent that degradation of sound quality hardly occurs.
Each of the convex portions is preferably provided integrally with the obverse surface of the protruding portion. According to this arrangement, the protruding portion and the convex portions can be easily molded integrally. Namely, in a case where the convex portions are provided integrally with the reverse surface of the edge portion of the opening, the convex portions project to the inner side of the edge portion of the opening when the front cabinet is molded of synthetic resin, thereby making it difficult to releasing a mold. However, if the convex portions are provided integrally with the obverse surface of the protruding portion, the factor for making it difficult to release the mold is eliminated. As for this aspect, a more detailed description will be given in the embodiment described later.
In this invention, as the above described, the top portion of each of the convex portions needs to be formed in a tapered or arcuate shape. To satisfy this requirement, each of the convex portions is preferably formed in a backward and forward elongated linear shape or in a spherical shape, for example.
In this invention, it is preferred that each of the convex portions be formed of a pair of projections provided at two adjacent positions, and that the top portion of each of the projections forming the pair of projections, the top portion is formed in the tapered or arcuate shape. As for an advantage of adopting this arrangement, a more detailed description will be given in the embodiment described later. Incidentally, in this case as well, each of the projections is preferably formed in a backward and forward elongated linear shape or in a spherical shape.
In this invention, the convex portions are preferably provided at the plurality of positions on the obverse surface of the protruding portion at intervals which do not cause the edge portion of the opening to droop down. According to this arrangement, a situation does not occur in which the edge portion of the opening droops down between adjacent ones of the convex portions and approaches the protruding portion, and the drooping portions collide with the protruding portion to generate the fluttering sound.
In this invention, it is preferred that the protruding portion is provided over upper, left, and right sides of one of the front cabinet and the rear cabinet, and that the convex portions are correspondingly arranged at least two positions on each of the upper, left, and right sides, and rib-like projecting pieces which are superposed on the reverse surface of the protruding portion at a position intermediate between the convex portions arranged at the two positions are provided on the other of the front cabinet and the rear cabinets. According to this arrangement, the rib-like projecting pieces can prevent from the protruding portion from being inwardly warped and deformed due to drooping down or the like. Consequently, it is possible to prevent a situation in which the protruding portion is inwardly warped and deformed to detach the convex portions from the edge portion of the opening. This contributes to suppressing occurrence of jounce in the fitted portion between the protruding portion and the edge portion of the opening.
In this invention, it is preferred that each of the rib-like protruding pieces has a function of sliding on the reverse surface of the projection portion while outwardly warping and deforming the protruding portion to guide the protruding portion to the inner side of the edge portion of the opening when the protruding portion is fitted to the inner side of the edge portion of the opening, and the rib-like projecting pieces outwardly press the protruding portion, and whereby the protruding portion is brought into contact with the reverse surface of the edge portion of the opening. According to this arrangement, since the protruding portion and the edge portion of the opening are slightly tensioned, the vibration itself of the fitting portion, which causes the occurrence of the fluttering sound, hardly occurs. In addition, since the situation in which each of the convex portions is detached from the edge portion of the opening due to the above-described warping deformation of the protruding portion is prevented more reliably, and the jounce in the fitting portion between the protruding portion and the edge portion of the opening is suppressed more reliably. Further, operating efficiency at the time of fitting the protruding portion to the edge portion of the opening is improved. This action of improving the operating efficiency is further promoted if a guide surface slanted rearward upward is provided on a tip of each of the convex portions.
In this invention, both of the front cabinet and the rear cabinet are preferably made of synthetic resin moldings.
Here, a description has been given of the cabinet in which one cabinet is the rear cabinet, and the protruding portion is provided on that rear cabinet, while the other cabinet is the front cabinet, and the cabinet is formed by fitting the protruding portion to the inner side of the edge portion of the opening of the front cabinet. However, the same also holds true with the cabinet in which one cabinet is the front cabinet, and the protruding portion is provided on that front cabinet, while the other cabinet is the rear cabinet, and the cabinet is formed by fitting the protruding portion to the inner side of the edge portion of the opening of the rear cabinet